1. Field of the Invention
This invention relates to a useful intraocular irrigating and enucleated eyeball preservative composition. More particularly, this invention relates to a useful intraocular irrigating and enucleated eyeball preservative composition containing an ascorbyl tocopheryl phosphate compound or a pharmacologically acceptable salt thereof.
2. Description of the Prior Art
With the recent progress and spread of ophthalmic surgery, inclusive of cataract surgery and operations for transplantation of the cornea, iris or vitreous body, there is a great need for satisfactory intraocular irrigating solutions for protecting the intraocular tissues in such operative procedures. If only inadequate provisions are available for the protection of intraocular tissues in ophthalmic operations and the tissues sustain physiological damage, the postoperative courses will be unfavorable with corneal opacity, glaucoma and retinitis ensuing at times. As the intraocular irrigating solution, one close to physiologic aqueous in composition is of course preferred but generally, so far, physiological saline, lactated Ringer's solution, BSS (Balanced Salt Solution) (trade name) and BSS PLUS (trade name) have been mostly employed for intraocular irrigation. However, these intraocular irrigating solutions are not effective enough to protect corneal (endothelial) cells which are most liable to sustain physiological damage in ophthalmic operations. Under the circumstances, the development of intraocular irrigating solutions with an improved functionality to protect the intraocular tissues, particularly corneal (endothelial) cells, has been awaited in earnest.
Meanwhile, in an operation for the implantation of an ocular tissue graft such as the cornea, retina or crystalline lens, the ocular tissue graft material isolated from a donor must be preserved in such a manner that it may retain its physiological function until it has been ultimately transplanted in a recipient. A number of enucleated eyeball preservatives have heretofore been proposed for upholding the physiological competence of enucleated globes but their efficacies insure a preservation period only about 2 weeks at most. For example, in Japan a glucose phosphate Ringer's solution containing 3.5% of dextran is in common use as a globe preservative today but the dextran (DX) penetrates into the cornea (epithelium, stroma and endothelium) in an early stage of preservation (within a few days) to draw in water into the tissues and reportedly induce marked corneal swelling. Moreover, it is reported that dextran weakens the joint between the corneal endothelium and Descemet's membrane to cause a hypofunction of endothelial cells. Accordingly, enucleated eyeball preservatives, typically those containing chondroitin sulfate (CS) instead of dextran, are being explored for development but none have overcome the above-mentioned disadvantages. After all, there is no eyeball preservative available today that is fully satisfactory.
Under the circumstances described above, the inventors of this invention explored the efficacies of ascorbyl tocopheryl phosphate compounds and their pharmacologically acceptable salts and discovered that these compounds have an excellent intraocular tissue-protecting action. Starting from the finding, the inventors did further research and arrived at an intraocular irrigating and enucleated eyeball preservative composition which is disclosed in this specification and claimed.